A great deal of time and effort has been devoted toward the objective of an upgraded, retrofittable, metal coke-oven door seal. An "upgraded" coke-oven door seal is one which has improved performance over existing seals in emission control and operation. The ultimate objective is to achieve a coke-oven door seal that is practically emission free. Reaching this objective is of great importance as the steel industry is presently faced with tough environmental regulations that limit the amount of by-product from the coking process which can legally be emitted into the atmosphere.
The present invention relates to a coke-oven door seal and more specifically to a self-adjusting, metal coke-oven door seal which can be used to replace any existing coke-oven door seal (e.g., a seal which has become ineffective due to use) without major modifications having to be made to the coke-oven door or the door handling equipment. In other words, the seal of the present invention is retrofittable. The coke-oven door seal of the present invention provides a better seal than currently existing door seals and is extremely effective in controlling emissions from the coking process (i.e., the present invention is an "upgraded" coke-oven door seal). Further, the coke-oven door seal of the present invention can be made to replace virtually any coke-oven door seal now in existence at a relatively low cost. Finally, the present invention relates to a coke-oven door sealing system which includes a coke-over door seal, a unique pivotable plunger system and a secondary seal. The unique pivotable plunge system and the secondary seal both provide for even greater emission control.
Coke-oven doors are placed at the ends of a coke-oven coking chamber. These doors are often times provided with a sealing strip to assure the coking chamber is sealed shut so that by-products of the coking process, such as carbon gases, do not escape the coking chamber and pollute the atmosphere. Such sealing strips are often ineffective because during repeated cycles of the coking process, they harden and warp. As a result, they do not effectively seal the coking chamber.
A seal is necessary in connection with a coke-oven door because the profile congruency of the coke-oven door with the door jamb can be poor due to warpage of the door or the jamb caused by the extreme heat of the coking process. Without the seal, emissions from the coking process would far exceed acceptable levels.
A number of different seals have been used in connection with coke-oven doors. For example, as noted above, many coke-oven doors are provided with a pliable sealing strip which is oriented in perpendicular relation with the door jamb surface. These sealing strips are unacceptable because they have a relatively short lifespan and therefore need to be replaced on a regular basis. Such replacement is expensive. Moreover, coke-oven doors with such sealing strips are often extremely difficult to repair.
Today, most coke-oven doors utilize metal-to-metal contact seals wherein an edge in perpendicular relation to the door jamb surface is mounted to a diaphragm element so that plungers may be used to bias the edge into contact with the door jamb. The contact between the metal edge of the seal and the metal door jamb surface creates a metal-to-metal contact seal. As such, the seal forms a metal-to-metal closure with the coke-oven door jamb.
Generally, a metal-to-metal contact seal is mounted on the body of the coke-oven door and held in place by latching bars which are inserted into hooks which are attached to the door jamb. In operation, pressure is exerted by springs or screws to hold the coke-oven door in place. This pressure actually moves the coke-oven door toward the oven chamber and thereby moves the metal seal into close proximity to the door jamb. At this point, latching pressure is carried to the door seal until the door stops engage the door jamb.
Many times the above steps do not move the seal edge into contact with the door jamb because of distortions in the door or jamb profile. If this happens and additional movement of the seal is required, such movement can be accomplished by plungers mounted on the door behind the coke-oven door seal. These plunger are used to supply pressure on the seal edge to force it into contact with the door jamb. The effective use of currently known plungers oftentimes requires the close attention of coke-oven plant workers to adjust the pressure applied by such plungers.
Existing coke-oven door seals, sealing strips and metal-to-metal contact seals are shown in various prior patents. For example, U.S. Pat. No. 2,579,917 discloses one type of sealing device for coke-oven doors that does not include a metal-to-metal edge contact. Another type of coke-oven door seal is disclosed in U.S. Pat. No. 4,741,808. In that patent, the invention consists of a coke-oven door seal which includes a metal sealing strip and a crowned metal diaphragm. One other type of coke-oven door seal is shown in U.S Pat. No. 4,919,764. That patent discloses an angled leaf spring and seal assembly.
Presently known metal-to-metal contact seals all suffer from one or more of the following problems:
1. The seal is not flexible in terms of conforming to large distortions in jamb profiles; PA1 2. The seal is not sufficiently heat resistant to avoid deforming during repeated cycles of the coking process; PA1 3. The seal needs to be consistently adjusted by coke-plant workers to account for warped doors and/or door jambs and to account for other changes in jamb profiles; PA1 4. The seal is not strong enough to hold in tight contact with the jamb surface during the coking process and thus is not effective in controlling emissions of the coking process; and PA1 5. The seal is not retrofittable to a wide variety of the coke-oven doors now in use and/or is not physically or mechanically suitable for use in steel plants.
The present invention is a novel type of metal-to-metal contact seal and sealing system that overcomes each of the above-referenced limitations of currently known metal-to-metal seals. The manner in which the present invention overcomes these limitations is discussed in detail below.